Overhead conductor cables are commonly suspended from a messenger cable typically made of high strength alloys. The messenger cable is supported on poles or towers with the conductor cable spacers arranged at spaced intervals along the messenger cable to suspend one or more conductor cables. Since many power circuits require three phase electric power, it is often convenient to suspend conductor cables in groups of three. A spacer supports all three conductor cables and simultaneously maintains the conductors in spaced relation.
If the advantages of suspending conductors in this manner are to be fully availed, it is essential that the spacer be easily attached to the messenger cable and to the conductor cables. To provide ease of attaching the spacer to the cables and to reduce the number of parts required, the means for retaining the cables in their respective seats of the spacer should accommodate cables of varying cross sectional diameters without requiring bushings, sleeves, grommets or the like.
The construction of the spacer should be such that all of its parts have both high mechanical and electrical strength and are durable in use. In addition, all parts of the spacer should be economical to manufacture and to assemble.
U.S. Pat. No. 4,020,277, issued Apr. 26,1977 to Hendrix Wire & Cable Corporation, the predecessor to the instant assignee, discloses a spacer for aerial cables. The spacer includes a body member having at least one generally arcuate cable retaining means adapted to engage a surface of the conductor cable and retain the cable in a concave seat of the spacer. One end of the cable retaining means is pivotally supported on the body member. Generally arcuate ratchet tooth means are provided adjacent the other end of the cable retaining means. Generally arcuate ratchet tooth means are also provided on the body member outwardly of the concave seat. The teeth of the retainer ratchet tooth means are engageable with the teeth of the body member ratchet tooth means when the retaining means is rotated about its pivotal support, thereby to firmly retain the conductor cable in the concave seat.
However, it has been found that the cable retainer may be dislodged by contact with branches or as the result of force imposed on the retainer due to a short circuit in one of the cables.
While unrelated to aerial cable spacers, there are patents which relate to the more general art of cable clamps. U.S. Pat. No 4,669,688 discloses a cable clamp which, when in a locked position, provides a protrusion with a tooth-like member which is held between a retaining member and an engaging member. U.S. Pat. Nos. 3,516,631, 4,128,918 and 4,609,171 disclose other similar cable clamps.
The structures shown in the above cable clamps are not adaptable to aerial cable spacers. For instance, one common difference from the aerial cable spacers such as shown in U.S. Pat. No. 4,020,277, is that the general cable clamps are limited to clamping cables of one or of a limited size in diameter. The aerial cable spacer of U.S. Pat. No. 4,020,277 is adapted to accommodate a greater range of cable sizes, with ease of replacing the cables and without reducing the effectiveness of the clamping ability of the cable retainer. In addition, the above general cable clamps have intricate components which are not durable for aerial cable spacer applications.